1. Field of the Invention
This invention relates generally to folding carts.
2. Prior Art
Rigid carts are commonly used for transporting people, animals or objects in homes, gardens, farms, factories and stores, and between different locations. For many uses, folding carts are preferable because they can be collapsed for compact storage and transportation when not in use. Folding carts are particularly suitable for transporting children, sporting goods, gardening items, and items purchased in open air markets. Folding carts are especially advantageous for use by families when traveling, because they can be folded to fit inside automotive trunks and other compact spaces. Various prior art folding carts are known. U.S. Pat. No. 2,421,751 to Giordano discloses one with a tubular fabric bag within a frame which is collapsible in two dimensions. The upper and lower corners of the bag are secured to the frame. When the cart is collapsed, the frame is slightly lengthened in the vertical direction. This is not a problem in the Giordano cart because it is very narrow. If the cart is changed to make it much wider than it is tall, it would not be collapsible because the bag will prevent the frame from extending adequately in the vertical direction. U.S. Pat. No. 3,945,660 to Zalewski discloses another two-dimensionally collapsible cart with a fabric bag. The top corners of the bag are rigidly attached to the frame, and the lower corners are attached to the frame by elastic bands which stretch when the frame is folded. If the elastic bands are loose enough to allow the frame to be easily folded, the bag will sag under a load. If the elastic bands are tight enough to prevent the bag from sagging under a load, they will make folding difficult.
U.S. Pat. Nos. 5,622,376 to Shamie and 5,687,984 to Samuel disclose folding carts with wheels at all four corners. When folded, the front wheels are positioned on top of the rear wheels for compactness, but the collapsed size of the cart is limited by the interference between the wheels and the frame members. Other known devices include a cart with wheels folded to laterally adjacent positions that take up more room. The lower corners of the bag are not connected to the frame, so that the bag will sag under a load. The bag is limited to a square shape. Any reduction in overall height will reduce the bag height by an equal amount.
Prior art carts typically have small wheels that cannot roll very well on soft or rough surfaces, such as a lawn or soil. Prior art carts also typically have frame members on each side of the cart that are completely parallel to each other when seen from the top. The top and bottom pivots between the sides are thus not vertically aligned with each other, so that the frame will bind during folding.
Accordingly, the objectives of the present folding cart are:
to be collapsible into a very compact shape to allow placement in compact spaces, such as an automotive trunk;
to have larger wheels for better rolling;
to be foldable into a very compact shape despite the large wheels;
to have a bag which does not sag under a heavy load;
to fold easily and smoothly;
to be strong and rigid enough when expanded;
to be lightweight;
to be producible in any height, length, and width; and
to be sufficiently rigid in the vertical and horizontal directions when expanded.
Further objectives of the present invention will become apparent from a consideration of the drawings and ensuing description.
The present folding cart is comprised of a rectangular bag and a flexible support panel positioned within a rectangular frame, and wheels connected to the frame by legs. The frame is comprised of pairs of scissoring members on the ends and sides for being quickly collapsible in two dimensions to a very compact shape. The ends of the scissoring members in each pair are offset toward each other to align the upper and lower corners of the frame so as to avoid binding during folding. An arched section is provided in each leg at one end of the frame that curve around the wheel at the other end of the frame when folded. Each arched section is engaged against an adjacent scissoring member for rigidity when the frame is expanded. A flexible bag is attached to the top corners of the frame, but not to the bottom corners to enable the frame to be collapsed. The flexible support panel is attached to the bottom corners of the frame to prevent the bag from sagging under a heavy load, and to improve rigidity in the horizontal directions.